Heat developing-out photosensitive materials

ABSTRACT

HEAT DEVELOPING-OUT PHOTOSENSITIVE MATERIALS CONSISTING OF THE FOLLOWING COMPONENTS: (A) A SUPPORT, AND (B) A LAYER COMPRISING THE FOLLOWING INGREDIENTS: (1) SILVER BENZOTRIAZOLE, (2) A SILVER HALIDE OBTAINED BY THE REACTION OF SIL VER BENZOTRIAZOLE AND AN INORGANIC HALIDE, (3) AS A REDUCING AGENT, ASCORBIC ACID, A DERIVATIVE THEREOF OR A 3-PYRAZOLIDONE DERIVATIVE (4) A BINDER, AND (5) A COMPOUND OF THE FORMULA   3-(HS-),4-R1,5-R2-1,2,4-TRIAZOLE   WHEREIN R1 REPRESENTS HYDROGEN OR ALKYL GROUP OR A GROUP OF THE FORMULA   R3-PHENYL   R2 REPRESENTS AN ALKYL GROUP OR A GROUP OF THE FORMULA   R3-PHENYL   AND R3 STANDS FOR HYDROGEN OR AN OMINO GROUP OF A GROUP OF THE FORMULA   -NH-CO-R4   AND R4 STANDS FOR AN ALKYL GROUP.

United States Patent 3,832,186 HEAT DEVELOPING-OUT PHOTOSENSITIVE MATERIALS Takao Masuda, Kinji Ohkubo, and Tadao Shishido, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Kanagawa, Japan No Drawing. Filed Apr. 26, 1973, Ser. No. 354,584

Claims priority, application Japan, Apr. 26, 1972, 47/41,967 Int. Cl. G03c 1/72, 1/34 US. Cl. 96-1141 30 Claims ABSTRACT OF THE DISCLOSURE R represents an alkyl group or a group of the formula and R stands for hydrogen or an amino group or a group of the formula NH-(HJR4 and R stands for an alkyl group.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to heat developing-out.

photosensitive materials, more precisely, to heat developing-out photosensitive materials which can yield a black image after being developed. Particularly, the present invention relates to heat developing-out photosensitive materials consisting of the following components:

( 1) silver benzotriazole,

(2) a silver halide obtained by the reaction of silver benzotriazole and an inorganic halide,

(3) a reducing agent,

(4) a binder, and

(5) an agent which imparts a black shade to the photosensitive material.

Description of the prior art Photographic processes using a silver halide have hitherto been most widely practised since such processes provide excellent photographic properties such as sensitivity and gradation as compared with the processes such as elecice trophotographic processes, diazo photographic processes, etc.

However, the silver halide photosensitive materials used in the silver halide photographic process require treatments such as stopping, fixation, water washing, stabilization, etc., so that when the material is exposed to form an image and is subjected to development using a developer the developed image is not discolored or faded by light or the part not developed (hereafter referred to as background) is not blackened. Thus, the process involves various problems such as it takes a long time for the treatments, the treatments involve chemical agents dangerous to humans and further the interior of the treating room as wellas the hands and the clothes of operators can be contaminated with the chemical agents. Under these circumstances, it would be desirable to improve photographic processes using a silver halide so that the silver halide photosensitive material used in the processes could be treated in the dry state without being subjected to treatment solutions and that the treated images would be stable.

Various studies have hitherto been made in an effort to improve such silver halide processes. One of them is a so-called one-bath development and fixation method wherein a development and a fixation are performed at the same time in a conventional silver halide photographic process, described, for example, in US. Pat. 2,875,048, British Pat. 954,453 and German Pat. 1,163,142. Another solution suggested is to try to convert the wet treatment which is performed in the present silver halide photographic process to a dry treatment, which is described, for example, in German Pat. 1,174,159 and British Pats. 943,476 and 951,644. Still another suggestion is to try to use as a main ingredient a photosensitive element such as a silver salt of an aliphatic carboxylic acid, e.g. behenic acid, or a silver salt such as silver saccharin or silver benzotriazole, and a catalytic amount of a silver halide described, for example, in Japanese Pats. 4,921/ 68, 4,924/68, 26,582/69, 18,416/70, 12,700/70 and 22,186/ 70 and British Pat. 1,205,500.

However, by the use of the heat developing-out photosensitive materials which have hitherto been proposed as in the last-mentioned method above, for example, a composition consisting of a silver salt of a carboxylic acid such as behenic acid or silver benzotriazole, a reducing agent and a catalytic amount of a silver halide, a black shaded image cannot be obtained. Therefore, in heat developing-out photographic materials including silver behenate, phthalazinone is further added in order to obtain 'a black shaded image.

However, phthalazinone which is effective in the known composition including silver behenate is not effective in the composition of the present invention including as an image forming compound silver benzothiazole. This will be substantiated in the comparative examples hereunder described.

Silver benzothiazole is superior to silver behenate as an image forming compound since the former is more stable to heat than the latter, and so heating fog hardly occurs in a photosensitive material including silver benzotriazole when the nonexposed part thereof is heated, and as a' result an image having good contrast between the image and the background is obtained. Therefore, it is desirable to provide compounds which are able to form an image of an excellent black shade in a heat developingout photosensitive material which includes silver benzotriazole.-

SUMMARY OF THE INVENTION The present invention belongs to the last class of methods described above and provide heat developing-out photosensitive materials including silver benzothiazole and a silver halide.

3 More precisely, the present invention is based upon the discovery that an image having an excellent black shade can be obtained using a heat developing-out photosensitive material which. comprises the following ingredients:

( 1) silver benzothiazole,

(2) a silver halide obtained by the reaction of silver benzotriazole and an inorganic halide,

(3) a reducing agent,

(4) a binder, and

(5) as an agent mainly to imparta black shade to the developed image at least one compound of the formula wherein R represents hydrogen or an alkyl group or a group of the formula where R represents an alkyl group or a group of the formula where R represents hydrogen or an amino group or a group of the formula and where R represents an alkyl group.

DETAILED DESCRIPTION OF THE. INVENTION With respect to the effect of the present heat developingout photosensitive materials, the effectiveness of a compound falling in the scope of the above mentioned compounds (5) can be determined by the test explained below.

The following ingredients are subjected to ball milling for several hours at about 25 C. under atmospheric pressure to make a dispersion.

G. Polyvinyl butyral 6 Silver benzotriazole 4 Isopropyl alcohol, 40 ml.

The thus prepared dispersion will hereafter be referred to as Dispersion A.

Next, a coating composition is formed using Dispersion A mixed with the following ingredients:

Dispersion A (mixed with the following four components in whole amount as above);

Methanol solution including 5% by weight of mercuric bromide and 8.5% by weight of mercuric iodide 1 iAcetone solution including 0.2%* by weight of benzoxazolilidene thiohydantoin sensitizing dye 1 Methyl Cellosolve solution including 25% by weight of ascorbic acid monopalmitate 8 Methyl Cellosolve solution including 5% by weight of a compound (5) of the present invention 1 The resulting composition is applied to a polyethylene terephthalate support such that the amount of the silver in the coated composition is 1.3 g. per 1 m? of the support. The thus formed coating is left under atmospheric 4 pressure at about 50-70 C. and dried to substantial solidity. This element is image-wise exposed to tungsten light for 2 minutes and then the thus exposed element is put between heated plates and heated for 30 seconds at C.

The resulting image is compared with an image obtained by using phthalazinone. It is confirmed that by using a compound (5) of the present invention an image of a black shade is obtained, While using phthalazinone an image of a brown shade is obtained. Specific working examples in this respect will be given in the following material.

Representatives of the compounds (5) suitable for the present invention are, for example, as follows:

Compound No. 1: 3-Mercapto-5-methyl-4-phenyl-1,2,4-

triazole Compound No. 2: 5-Ethyl-3-mercapto-4-phenyl-1,2,4-triazole H5C2-i=-N Compound No. 3: 3-Mercapto-5-pentyl-4-phenyl-1,2,4-

triazole m.p. 177 C.

Compound No. 4: 4,5-Diphenyl-3-mercapto-1,2,4-triazole S H 1 -N N I m.p. 280 C N Compound No. 5: 3-Mercapto-4-phenyl-5-undecyl-1,2,4-

triazole I I mp. 103 C nOfHaa Compound No. 6: 4,5-Diethyl-3-mercapto-1,2,4-triazole Compound No. 8: 4-Ethyl-3-mercapto-5-phenyl-1,2,4-triazole C CzHs-N N I m.p. 145 C.

Compound No. 9: 5-p-Aminophenyl-4-ethyl-3-mercapto- 1,2,4-triazole m.p.245C

Compound No. 5-p-Acetoamidephenyl-4-ethyl-3- mercapto-1,2,4-triazole HsC.C.N

Compound No. 11: S-p-Capronamidephenyl-4-ethyl-3- mercapto-l,2,4-triazole I C=N n0 EH11. C .N H H 0 mp. 216C Compound No. 12:

mercapto-1,2,4-triazole 4-Ethyl-5-p-lauroamidephenyl-3- Synthesis Example 1 (Compound No. 2)

10 g. of 4-phenyl thio-semicarbazide are dissolved in 80 cc. of pyridine and are stirred while being cooled with ice, and then 8 g. of propionyl chloride are gradually added to the resulting solution. After the completion of the addition, the solution is further stirred for 1 hour while being cooled with ice. The reaction mixture solution is added to ice-water and the crystalline precipitates formed are collected by filtration. The thus collected crystalline precipitates are put in cc. of 10% sodium hydroxide solution and are heated for 2 hours on a water bath. The reaction solution is cooled and acidified with hydrochloric acid and then the resulting crystalline precipitates are collected by filtration. The precipitates are recrystallized from ethanol, whereby 6 g. of needle-like crystalline products having a melting point of 177 C. are obtained.

Synthesis Example 2 (Compound No. 3)

10 g. of 4-phenyl thio-semicarbazide are dissolved in 80 cc. of pyriidne and 8 g. of caproyl chloride are gradually added to the resulting solution while it is being stirred and cooled with ice. The remainder of the process is the same as Synthesis Example 1. The resulting crystalline precipitates are recrystallized from ethanol whereby 7 g. of needle-like crystalline products having a melting point of 136-137 C. are obtained.

Synthesis Example 3 (Compound No. 6)

9 g. of 4-ethyl thio-semicarbazide are dissolved in 50 cc. of pyridine, and 10 g. of propionyl chloride are gradually added to the resulting solution while it is being stirred and cooled with ice. The remainder of the process is the same as in Synthesis Example 1. The resulting crystalline precipitates are recrystallized from water, whereby 6 g. of needle-like crystalline products having a melting point of 148 C. are obtained.

Synthesis Example 4 (Compound No. 8)

9 g. of 4-ethyl thio-semicarbazide are dissolved in 50 cc. of pyridine, and 15 g. of benzoyl chloride are gradually added to the resulting solution while it is being stirred and cooled with ice. The remainder of the process is the same as in Synthesis Example 1. The resulting crystalline precipitates are recrystallized from a solvent mixture consisting of water and ethanol, whereby 9 g. of needle-like crystalline products having a melting point of 145 C. are obtained.

Synthesis Example 5 (Compound No. 9)

12.5 g. of p-acetoarnidebenzoyl hydrazine are dissolved in cc. of ethanol, and 10 cc. of ethyl thio-isocyanate added thereto. The resulting mixture is refluxed under heat for 2 hours. After being cooled, the resulting crystalline precipitates are collected by filtration and are added to 20 cc. of a 10% sodium hydroxide aqueous solution. The resulting solution is refluxed under heat for 2 hours on a water bath. After being cooled, the solution is acidified with hydrochloric acid and the resulting crystalline precipitates are collected by filtration and are recrystallized from ethanol. 9 g. of a needle-like crystalline product having a melting point of 244-245" C. are obtained.

The amount of the compound or compounds of formula (5) to be added which are effective as a black shade imparting agent in the present invention is preferably 0.0001-1 mol per 1 mol of silver benzotriazole. This amount may vary, depending upon the kind of the compound to be used, the kinds of the respective ingredients in the photosensitive material, treating temperature, etc., but the above range covers most commercial embodiments.

The silver benzotriazole used in the present invention is a silver salt which is stable to light, and only in parts wherein exposed silver halide is present and which are heated, is the silver salt reduced by the action of a reducing agent to form a silver image.

The absolute amount of the silver benzotriazole present in the element can vary greatly, and is not particularly limited so long as a sufiicient amount is present to form an acceptable image. Generally speaking from about 0.5 to about 10 g. of silver benzotriazole will be present per square meter of support, more preferably 1 g. to 6 g. At lesser amounts, occasionally inferior results will be obtained, while no better effect is obtained at greater amounts as compared to about 10 g./m.

The reducing agents to be used in the present invention must be ones which are suitable for reducing silver benzotriazole upon being heated in the presence of the exposed silver halide to form the silver image, as mentioned above. On the other hand, the silver benzotriazole is more stable to heat than silver behenate as already explained, and so it is hardly reduced under heat. Therefore, known reducing agents which are eifective with silver behenate are almost ineffective for silver benzotriazole, since the reducing ability of such known reducing agents is weak and so the silver benzotriazole is reduced only with difficulty.

'It has been found that ascorbic acid and/ or an ascorbic acid derivative is (are) a suitable reducing agent which is effective for reducing silver benzotriazole. This is described, for example, in Japanese Pat. 22,185/ 70. Representatives of the efiective ascorbic acid derivatives are, for example, as follows: ascorbic acid monoor di-fatty acid esters such as ascorbic acid monolaurate, monomyristate, monopalmitate, monostearate, monobehenate, dilaurate, dimyristate, dipalmitate, distearate, dibehenate, etc. In addition, D-aroascorbic acid also is preferred as a reducing agent suitable in the present invention. Another group of reducing agents which are suitable in the present invention are 3-pyrazolidone derivatives. Representatives of these derivatives are, for example: 1-phenyl-3-pyrazolidone, l-phenyl-4-methyl 3 pyrazolidone, 1-p-methylphenyl-3-pyrazolidone, l-phenyl-S-carboxy-3-pyrazolidone, l-phenyl 4,4 dimethyl-3-pyrazolidone, 1-phenyl-5-carboxyethyl-3-pyrazolidone, l-phenyl-5,5-dimethyl 3 pyrazolidone, 1-phenyl-5-methyl-3- pyrazolidone, etc.

A mixture of ascorbic acid or derivatives thereof, a mixture of 3-pyrazolidone derivatives, or a mixture of ascorbic acid or derivatives thereof and 3-pyrazolidone derivatives may also be used if desired.

While the term derivatives is broad, it is purposefully used by applicants because there is no particular limitation on the exact derivative used, so long as it serves an adequate reducing function in the element and exerts no harmful influence on element properties. The suitability of any particular derivative can be determined by a simple test, i.e., a trial run series of elements are prepared, exposed, etc., and the final material observed. If an acceptable image results for the use contemplated, the derivative can be used.

The amount of the reducing agent used in the present invention is preferably 0.1-5 mols per 1 mol of silver benzotriazole.

The silver halides used in the present invention are those which have been manufactured from silver benzotriazole and an inorganic or organic halide by reacting a part of the silver benzotriazole with the halide to form a silver halide, as mentioned above. For example, as in the test method explained hereinbefore, the silver halides may be prepared merely by adding a solution of an inorganic halide such as mercuric bromide and/ or mercuric iodide solution to a polymer dispersion of silver benzotriazole. The reaction of a part of the silver benzotriazole with the halide to form a silver halide can clearly be seen by observing the variation of the corresponding X-ray diffraction patterns. The amount of silver benzotriazole reacted with inorganic halide is merely selected so as to provide a sufiicient amount of silver halide and a sufiicient amount of silver benzotriazole after reaction for purposes of image formation. Generally, from 5 mole to 0.5 mole of inorganic halide is reacted with 1 mole of silver benzotriazole to form silver halide in an equivalent amount.

As the preferred inorganic halides there are mentioned, for example, hydrogen bromide, hydrogen iodide, ammonium bromide or ammonium iodide, or a metal halide such as a metal chloride, bromide or iodide, e.g., strontium, cadmium, zinc, chromium, sodium, potassium, barium, iron, cesium, lanthanum, copper, nickel, magnesium, aluminum, antimony, cobalt, mercury, lead, beryllium, cal cium, tin, gold, lithium, manganese, gallium, indium, rho dium, ruthenium, palladium, iridium, platinum and tellurium and the like, -chloride, -bromide, or -iodide. The metal used is not particularly limited, and these compounds can generally be represented by the formula MX where M is hydrogen, ammonium or a metal, X is the halide and n is the valence of M.

The amount of inorganic halide added is preferably /10000.5 mol per 1 mol of silver benzotriazole.

The heat developing-out photosensitive material compositions of the present invention can be incorporated in a binder.

Suitable substances for the binder are, in general, hydrophobic, but hydrophilic substances can also be utilized. These are transparent or semi-transparent and are natural substances such as gelatin, gelatin derivatives and cellulose derivatives as well as synthetic polymer substances such as polyvinyl compounds, acrylamide polymers, etc. Other synthetic polymer compounds which may also be used are, e.g., latex-type dispersed vinyl compounds. Further preferred high molecular weight substances and resins used as binders include, for example, polyvinyl butyral, cellulose acetate butyrate, polymethyl methacrylate, polyvinyl pyrrolidone, ethyl cellulose, polystyrene, polyvinyl chloride, chlorinated rubber, polyisobutylene, butadienestyrene copolymers, vinyl chloride-vinyl acetate copolymers, vinyl acetate-vinyl chloride-maleic acid copolymers, polyvinyl alcohol, etc. The amount of the binder used is preferably in the range of 4: 1-124 by weight on the basis of silver benzotriazole.

For the heat developing-out photosensitive materials of the present invention, various kinds of supports can be utilized. Representatives of the supports are, for example, cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film and polycarbonate film, as well as other resin substances and glass, paper, metal, etc. The support should be resistant to any processing conditions involved.

On the heat developing-out photosensitive materials of the present invention an antistatic layer or a conductive layer may be provided. Further, an antihalation substance and an antihalation dye may also be incorporated in the materials.

The present photosensitive materials may optionally include a matting agent for example, starch, titanium dioxide, zinc oxide, silicon dioxide, etc. In addition, a fluorescent whitening agent from the stilbene series, triazine series, oxazole series or coumarin series of fluorescent whitening agents may also be incorporated in the present photosensitive materials.

The heat developing-out light sensitive layer used in the present invention may be applied to a support by various coating methods. These coating methods include, for example, an impregnation method, an air knife method and a curtain coating method, as well as an extrusion coating method as described in U.S. Pat. 2,681,294 wherein a hopper is used for the extrusion. If desired, two or more layers may be applied at the same time.

An optical sensitizing dye can advantageously be used in the present invention for the purpose of imparting further sensitivity to the light-sensitive elements. For example, a solution or a dispersion of an organic solvent including the sensitizing dye is added, whereby the elements are further optically sensitized. The optical sensitizing agents which may be used in the present invention are, for example, cyanine dyes, merocyanine dyes, etc.

A latent image which is formed in the above mentioned heat developing-out photosensitive materials after exposure to light such as a xenon lamp, tungsten lamp, mercury-vapor lamp, etc., may be developed merely by heating the elements. Accordingly, the present invention also provides a process for developing a latent image in elements of exposed heat developing-out photosensitive 9 material by heating the elements up to about 100160 C. until a desired image is developed.

The developing temperature is preferably 100-l60 C., and in general 110140 C. is used. By prolonging or reducing the heating period, any higher temperature or lower temperature may be taken in the temperature range mentioned above. A developed image which is stable is obtained in general after a heat treatment of 1-60 seconds.

As the heating means for the said development, various kinds of heat imparting means may be used. The above mentioned elements may be contacted with a simple heating plate, or may be contacted with a heated drum. As the case may be, the elements may be passed through the interior of a heated area. Further, the elements may also be subjected to high frequency induction heating.

The present invention will now be explained in more detail by several working Examples.

EXAMPLE 1 Dispersion A was formed as heretofore described. The respective ingredients of the Dispersion A were mixed for 4 hours in a ball mill. Next, a composition was prepared by mixing the following components:

Ml. Dispersion A 40 Methanol solution including by weight of mercuric bromide and 8.5% by weight of mercuric iodide 1 Acetone solution including 0.2% by weight of benzoxazolilidene thiohydantoin sensitizing dye 1 Methyl Cellosolve solution including by weight of ascorbic acid monopalmitate 8 Methyl Cellosolve solution including 5% by weight of 3-mercapto-5-methyl-4-phenyl-1,2,4-triazole 1 The resulting composition was applied on a polyethylene terephthalate film support so that the thickness of the coated layer was 80p. (in the wet state) at 50 C. The thus coated substance was dried for 1 hour at 70 C. under atmospheric pressure, whereby a heat developing-out photosensitive material was prepared.

Next, the resulting material was sensitometrically exposed to tungsten light for 2 minutes. Thereafter, the material was put between metal plates which were heated to 130 C. and was heated for seconds therebetween. A black shade image was obtained.

Following the same steps as mentioned above except omitting 3-mercapto-S-methyl-4-phenyl-1,2,4-triazole, a control element was prepared for sake of comparison and subjected to exposure as above. The resulting image had a yellowish brown shade and the density of the image was quite faint.

As another comparison, an element was prepared according to the same steps as mentioned above while an equivalent amount of phthalazinone was used in place of the 3-mercapto-5-methyl-4-phenyl-1,2,4-triazole. The resulting element was exposed as above and subjected to the same treatments. The resulting image had a brown shade and the density thereof was faint.

As still another comparison, an element was prepared using an equivalent amount of 3-mercapto-4-phenyl-1,2,4- triazole which has hitherto been used as a shade imparting agent (refer to Japanese Patents 18,416/70, 12,700/70 and 26,582/ 69). The thus prepared element was exposed and treated as above. The resulting image had a somewhat blackish but almost brown shade. The density thereof was also faint.

A further comparison element was prepared using an equivalent amount of 1,3-diphenyl guanidine for the triazole, the former being a known shade imparting agent (refer to Japanese Patent 12,700/70) and exposed and treated as above. The resulting image had a blackish brown shade, but the density thereof was good.

From the above experimental data, the following facts will be noted: It is apparent that phthalazinone which is The procedure of Example 1 was followed except 3- mercapto-S-pentyl-4-phenyl-1,2,4-triazole was used in place of 3-mercapto-5-methyl-4-phenyl-1,2,4-triazole. An image having a good black shade was obtained as in Example l. 1

EXAMPLE 3 The procedure of Example 1 was followed except 4,5- diethyl-3-mercapto-1,2,4-triazole was used in place of 3- mercapto-5-methyl-4-phenyl-1,2,4-triazole. An image having a good black shade was obtained as in Example 1.

EXAMPLE 4 The procedure of Example 1 was followed except 4- ethyl-3-mercapto-5-phenyl-l,2,4-triazole was used in place of 3-mercapto-5-ethyl-4-phenyl-1,2,4-triazole. An image having a good black shade was obtained as in Example 1.

EXAMPLE 5 The procedure of Example 1 was followed except 5-pcapronarnide-phenyl-4-ethyl-3-mercapto-1,2,4-triazole was used in place of B-mercapto-5-methyl-4-phenyl-1,2,4-triazole. An image having a good black shade was obtained as in Example 1.

EXAMPLE 6 A composition was prepared by mixing the following components:

Ml. Dispersion A 40 Methanol solution including 6% by weight of zinc bromide and 9% by weight of zinc iodide 1 Chloroform solution including 0.2% by weight of benzoxazolilidene rhodanine sensitizing dye 1 Methyl Cellosolve solution including 25 by weight of 1-phenyl-3-pyrazolidone 8 Methyl Cellosolve solution including 3% by weight of 4-ethyl-3-mercapto-5-pentyl-1,2,4-triazole 0.5

The resulting composition was applied to a polyethylene terephthalate film support such that the thickness of the coated layer was (wet state) at 50 C. The thus coated substance was dried for 1 hour at 70 C. under atmospheric pressure, whereby a heat developing-out photosensitive material was prepared. Next, the element was sensitometrically exposed to a xenon flash lamp for 10* second. Thereafter the material was put between metal plates which were heated to C. and was heated for 30 seconds. A black shade image was obtained.

EXAMPLE 7 The procedure of Example 6 was followed except 5-pcapronamide-phenyl-4-ethyl-3-mercapto-l,2,4-triazole was used in place of 4-ethyl-3-mercapto-5-pentyl-1,2,4-triazole. An image having a black shade was obtained as in Example 6.

EXAMPLE 8 The procedure of Example 6 was followed except 1- phenyl-4,4dimethyl-3-pyrazolidone was used as a reduc- 1 1 ing agent in place of 1-pheny1-3-pyrazolidone. An image having a black shade was obtained as in Example 6, but the maximum density of the image was only 80% of that of the image obtained in Example 6.

EXAMPLE 9 A composition was prepared by mixing the following components:

Dispersion A 4O Methanol solution including 5% by weight of mercuric bromide 1 Acetone solution including 0.2% by weight of benzoxazolilidene thiohydantoin sensitizing dye 1 Methyl Cellosolve solution including 25% by weight of ascorbic acid monomyristate 8 Methyl Cellosolve solution including 5% by weight of 3-mercapto-5-phenyl-4-phenyl-1,2,4-triazole 1 85:15) g 15 Tetrahydrofuran ml 100 The resulting composition was superimposed on the above coated substance such that the thickness of the newly coated layer was 60 (wet state) at 50 C. The thus coated substance was dried for 1 hour at 70 C. under atmospheric pressure.

In the thus prepared heat developing-out photosensitive material, the degree of transparency of the coated layer increased. A material having such high transparency is more preferred as compared with the other materials not having an over-coated layer, for example, for intermediates.

Next, the elements in the resulting material were sensitometrically exposed to a tungsten lamp for 30 seconds. Thereafter, the material was put between metal plates which were heated to 120 C. and heated for 20 seconds. A black shade image was obtained. As compared with the material wherein the over-coated layer was omitted, the maximum density of the resulting image increased to 1.3 times that of the comparative case.

EXAMPLE The same steps as in Example 9 were followed except a mixture of ascorbic acid monostearate and A part of 1-phenyl-3-pyrazolidone was used as a reducing agent in place of the ascorbic acid monomyristate.

A black shade image was obtained as in Example 9, and by heating the same for 10 seconds at 120 C. the maximum density of the resulting image was the same as in Example 9.

EXAMPLE 11 The procedure of Example 9 was followed except a Dispersion B prepared as hereunder described was used in place of Dispersion A. Manufacture of Dispersion B.

The following components were subjected to ball milling for 4 hours at about 25 C. under atmospheric pressure:

G. Ethyl cellulose 6 Silver benzotriazole 4 Isopropyl alcohol, 40 ml.

An image having a black shade was obtained as in Example 9.

12 EXAMPLE 12 A composition was prepared by mixing the following components:

The resulting composition was applied on a photographic base paper such that the thickness of the coated layer was 1001.1. (wet state) at 50 C. The thus coated substance was dried for 30 minutes at 50 C. under atmospheric pressure. The resulting heat developing-out photosensitive material was sensitometrically exposed to tungsten light for 30 seconds. Next, the material was put between metal plates which were heated to C. and was heated for 15 seconds. A black shaded image was obtained.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

What is claimed is:

1. Heat developing-out photosensitive materials comprising the following substances:

(a) a support, and

(b) a layer comprising the following ingredients:

(1) silver benzotriazole,

(2) a silver halide obtained by the reaction of silver benzotriazole and an inorganic halide,

(3) as a reducing agent, a compound selected from ascorbic acid and a derivative thereof and a 3- pyrazolidone derivative,

(4) a binder, and

(5) a compound of the formula wherein R represents hydrogen or an alkyl group of the formula where R represents an alkyl group or a group of the formula and R stands for hydrogen or an amino group or a group of the formula where R stands for an alkyl group. 2. Heat developing-out photosensitive materials as claimed in Claim 1 wherein compound (5) is selected from the group consisting of:

3-mercapto-5-methyl-4-phenyl-1,2,4-triazole, S-ethyl-3-mercapto-4-phenyl- 1,2,4-triazo1e, 3-mercapto-5-penty1-4-phenyl- 1 ,2,4-triazole, 4,5 -diphenyl-3-mercapto-1 ,2,4-triazole, 3-mercapto-4-phenyl-5-undecyl1,2,4-triazole,

'13 4,5-diethyl-3-mercapto-1,2,4-triazole, 4-ethyl-3-mercapto-5-pentyl-1,2,4-triazole, 4-ethyl-3-mercapto-S-phenyl-1,2,4-triazole, -p-aminophenyl-4-ethyl-3-mercapto-1,2,4-triazole, 5-p-acetoamide-phenyl-4-ethyl-3-mercapto-1,2,4-triazole, 5-p-capronamide-phenyl-4-ethyl-3-mercapto-1,2,4-triazole and 4-ethyl-5-p-lauroamide-phenyl-3-mercapto-1,2,4-triazole.

3. Heat developing-out photosensitive materials as claimed in Claim 1 wherein compound (5) is used in an amount of 0.0001-1 mol per 1 mol of silver benzotriazole.

4. Heat developing-out photosensitive materials as claimed in Claim 1 wherein ascorbic acid is used as the reducing agent.

5. Heat developing-out photosensitive materials as claimed in Claim 1 where the reducing agent is an ascorbic acid monoor di-fatty ester.

6. Heat developing-out photosensitive materials as claimed in Claim 1 wherein an ascorbic acid derivative selected from the group consisting of ascorbic acid monolaurate, mono-myristate, mono-palmitate, mono-stearate, mono-behenate, di-laurate, di-myristate, di-palmitate, distearate and di-behenate is used as the reducing agent.

7. Heat developing-out photosensitive materials as claimed in Claim 1 wherein a 3-pyrazolidone derivative selected from the group consisting of l-phenyl-3-pyrazolidone, l-phenyl-4-methyl 3 pyrazolidone, l-p-methylphenyI-S-pyrazolidone, l-phenyl-S-carboxy-3-pyrazolidone, 1-phenyl-4,4-dimethyl 3 pyrazolidone, l-phenyl-S-carboxyethyl-3-pyrazolidone, 1-phenyl-5,5dimethyl-3-pyrazolidone and 1-phenyl-5-methyl-3-pyrazolidone is used as the reducing agent.

8. Heat developing-out photosensitive materials as claimed in Claim 1 wherein a mixture of ascorbic acid or derivatives thereof, a mixture of 3-pyrazolidone derivatives, or a mixture of ascorbic acid or derivatives thereof and 3-pyrazolidone derivatives is used as the reducing agent.

9. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the reducing agent is used in an amount of 0.1-5 mols per 1 mol of silver benzotriazole.

10. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the silver halide is one obtained by the reaction of silver benzotriazole and an inorganic halide selected from the group consisting of hydrogen bromide, hydrogen iodide, ammonium bromide or ammonium iodide, or a metal chloride, bromide and iodide.

11. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the silver halide is added in an amount of l/1000-0.5 mol per 1 mol of silver benzo triazole.

12. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the binder is a hydrophobic or hydrophilic transparent or semi-transparent substance.

13. Heat developing-out photosensitive materials as claimed in Claim 12 wherein the binder is a resin selected from the group consisting of polyvinyl butyral, cellulose acetate butyrate, polymethyl methacrylate, polyvinyl pyrrolidone, ethyl cellulose, polystyrene, polyvinyl chloride, chlorinated rubber, polyisobutylene, butadienestyrene copolymer, vinyl chloride-vinyl acetate copolymer, vinyl acetate-vinyl chloride-maleic acid terpolymer and polyvinyl alcohol.

14. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the binder is used in an amount of 4: 1l:4 by weight on the basis of silver benzotriazole.

15. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the support is selected from the group consisting of cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film, glass, paper and metal.

16. Heat developing-out photosensitive materials as claimed in Claim 1 wherein an antistatic layer or a conductive layer is provided on the layer.

17. Heat developing-out photosensitive materials as claimed in Claim 1 wherein an antihalation substance and/or an antihalation dye is incorporated in the layer.

18. Heat developing-out photosensitive materials as claimed in Claim 1 wherein a matting agent is included in the layer.

19. Heat developing-out photosensitive materials as claimed in Claim 1 wherein a fluorescent whitening agent is incorporated in the layer.

20. Heat developing-out photosensitive materials as claimed in Claim 1 wherein an optical sensitizing dye is incorporated in the layer.

21. Heat developing-out photosensitive materials as claimed in Claim 1 wherein the silver benzotriazole is present in an amount of from about 0.5 to about 10 g./m. of support.

22. Heat developing-out photosensitive materials as claimed in Claim 21 where components (2)-(5) are present in the following proportions; per mol of silver benzotriazole:

(2) 0001-05 mol per mol of silver benzotriazole;

(3) 0.1-5 mol per mol of silver benzotriazole;

(4) 4:11:4 parts per weight part of silver benzotriazole; (5) 0.0001-1 mol per mol of silver benzotriazole.

23. Heat developing-out photosensitive materials as claimed in Claim 22 where when R R or R in compound (5) is al-kyl, it is C -C alkyl, where the binder is at least semitransparent and is an organic polymer substance.

24. Heat developing-out photosensitive materials as claimed in Claim 23 where compound (5) is selected from the group consisting of 3-mercapto-5-methyl-4-phenyl- 1,2,4 triazole, 5-ethyl-3-mercapt0-4-phenyl-1,2,4-triazole, 3-mercapto-5-pentyl-4-pheuyl-1,2,4-triazole, 4,5-diphenyl- 3-mercapto-1,2,4-triazole, 3-mercapto-4-phenyl-S-undecyl- 1,2,4-triazole, 4,5-diethyl 3 mercapto-1,2,4-triazole, 4- ethyl-3-mercapto-5-pentyl 1,2,4 triazole, 4-ethyl-3-mercapto-S-phenyl-1,2,4-triazole, 5-p-aminophenyl-4-ethyl 3- mercapto-l,2,4-triazole, 5-p-acetoamide-phenyl-4-ethyl-3- mercapto1,2,4-triazole, 5-p-capronamide-phenyl-4 ethyl- 3-mercapto-l,2,4-triazole and 4-ethyl 5 p lauroamidephenyl-3-mercapto-1,2,4-triazole.

25. Heat developing-out photosensitive materials as claimed in Claim 24 Where the reducing agent is selected from the group consisting of: ascorbic acid, ascorbic acid mono-laurate, mono-myristate, mono-palmitate, monostearate, mono-behenate, di-laurate, di-myristate, dipalmitate, di-stearate and di-behenate, 1-phenyl-3-pyrazolidone, l-phenyl-4-methyl 3 pyrazolidone, l-p-methylphenyl-S-pyrazolidone, 1-phenyl5-carboxy-3-pyrazolidone 1-phenyl-4,4-dimethyl-3-pyrazolidone, l-phenyl-S-carboxyethyl-3-pyrazolidone, l-phenyl 5,5 dimethyl-3-pyrazolidone and l-phenyl-S-methyl-3-pyrazolidone, or a mixture thereof.

26. Heat developing-out photosensitive materials as claimed in Claim 25 where the inorganic halide is of the formula MX where X is chloride, bromide or iodine, n is the valence of M, and M is selected from the group consisting of hydrogen, ammonium, strontium, cadmium, zinc, chromium, sodium, potassium, barium, iron, cesium, lanthanum, copper, nickel, magnesium, aluminum, antimony, cobalt, mercury, lead, beryllium, calcium, tin, gold, lithium, manganese, gallium, indium, rhodium, ruthenium, palladium, iridium, platinum and tellurium.

27. Heat developing-out photosensitive materials as claimed in Claim 26 where the silver halide is formed by the reaction of silver benzotriazole and mercuric bromide and mercuric iodide, the reducing agent is an ascorbic acid monoester, the binder is polyvinyl butyral and compound References Cited (5) is 3-mercapto-5-methy1-4-phenyl-1,2,4-triazole. U I STATES PATENTS 28. A process for developing a latent image which has 3,617,289 11/1971 Ohkubo et a1 96 95 been formed in elements of exposed heat developing-out 5 3,645,739 2/1972 Ohkubo et a1 96-67 photosensitive materials as claimed in Claim 1, by heating 3,700,457 0/ 1 Y q iSt 96-114.1 the said elements up to about 100-160 C. until a desired 3,756,829 9/1973 Ohkubo et a1 96 '114'1 image is devemPed- RONALD H. SMITH, Primary Examiner 29. A process as claimed in Claim 28 where the heating is to 110140 C.

30. A process as claimed in Claim 28 where the heating Us, CL X,R is for 1-60 seconds. 96-109, 114

10 A. T. SUTRO PICO, Assistant Examiner 

